impacts are concentrated onto finfish and mollusc species, especially at larval stages.
Acidification disrupts the fixation of calcium carbonate (CaCO 3 ) on skeletons or
shell frames and affects physiological processes due to hypercapnia (LacoueLabarthe et al. 2016).
The scientific community has intensively studied the relationship between marine
environmental conditions and fish stocks and especially global warming. Marine
environmental conditions are also closely related to climate. Particularly, the evolution of climate affects the evolution of the ecosystem functions that influence the
reproduction and growth of commercial fish stocks and other aspects of the biology
and habits of these stocks (Sharp 1995). Small pelagic fish stocks, including clupeids
such as sardine or anchovy, have been the most strongly affected by these changes
over short and long timescales. These stocks have been strongly affected due to their
diet based on plankton, their migratory habits, their short reproductive and life
cycles, or their ability to cope with these changes (Hunter and Alheit 1997;
Klyashtorin 2001), although these relationships are also found in benthopelagic
fish species (Lim et al. 2003).
Several articles focused on the Alboran Sea small pelagic fish stocks. Giráldez
and Abad (2000) determined the spawning period of anchovy (from April–March to
September–October) and showed a high correlation between the gonado-somatic
index (GSI) of this fish species and temperatures of the previous month for both
sexes. García et al. (2003) detected a higher concentration of larvae at the surface
where chlorophyll concentration is also higher, coinciding with a decrease of mean
temperatures from 2000 to 2001. They also typified Malaga Bay as nursery area for
anchovy, as done before by García et al. (1981) who also showed a high spatial
correlation with mesoplankton distribution. Relatively low temperatures increase
primary production and consequently induce higher anchovy larval concentration
and higher growth rate. The aforementioned causality is supported by the results of
acoustic stock assessment campaigns that concluded that anchovy biomass increased
from 1716 T to 13,000 T during the period 2000–2001 (García et al. 2003). Agostini
and Bakun (2002) looked in the causes of the significant increase of anchovy fish
stock in period 2000–2001, stressing the existence of an important upwelling
process in the Alboran Sea area during 2001 related to the Atlantic flow through
the Strait of Gibraltar to the Mediterranean Sea as noted before by Cano and Gil
(1984). This upwelling process caused an increase of primary production in Malaga
Bay which resulted in a higher concentration of larvae and individual growth mainly
due to climate and marine environment factors (Macías et al. 2014). It has also been
demonstrated that kinetic energy levels in the NW Alboran region related to wind
regimes favor seasonal upwelling of small pelagic species in the Alboran Sea area
(Ruiz et al. 2013).
Mafalda et al. (2008) compared Spanish Institute of Oceanography stock assessments of 1993 and 1994 analyzing the relationship between Atlantic, Mediterranean,
and mixed water masses and the existence of larvae of different fish species. These
authors showed that the abundance of anchovy larvae was three times higher in 1994
than in 1993. They noted that the increase of fish stocks coincided with SST that was
relatively lower in 1994, namely, between 17
C and 20
C in 1994 and between
22 Fisheries Economics and Management Under the Impact of Human and Varying. . .
769
Acidification disrupts the fixation of calcium carbonate (CaCO 3 ) on skeletons or
shell frames and affects physiological processes due to hypercapnia (LacoueLabarthe et al. 2016).
The scientific community has intensively studied the relationship between marine
environmental conditions and fish stocks and especially global warming. Marine
environmental conditions are also closely related to climate. Particularly, the evolution of climate affects the evolution of the ecosystem functions that influence the
reproduction and growth of commercial fish stocks and other aspects of the biology
and habits of these stocks (Sharp 1995). Small pelagic fish stocks, including clupeids
such as sardine or anchovy, have been the most strongly affected by these changes
over short and long timescales. These stocks have been strongly affected due to their
diet based on plankton, their migratory habits, their short reproductive and life
cycles, or their ability to cope with these changes (Hunter and Alheit 1997;
Klyashtorin 2001), although these relationships are also found in benthopelagic
fish species (Lim et al. 2003).
Several articles focused on the Alboran Sea small pelagic fish stocks. Giráldez
and Abad (2000) determined the spawning period of anchovy (from April–March to
September–October) and showed a high correlation between the gonado-somatic
index (GSI) of this fish species and temperatures of the previous month for both
sexes. García et al. (2003) detected a higher concentration of larvae at the surface
where chlorophyll concentration is also higher, coinciding with a decrease of mean
temperatures from 2000 to 2001. They also typified Malaga Bay as nursery area for
anchovy, as done before by García et al. (1981) who also showed a high spatial
correlation with mesoplankton distribution. Relatively low temperatures increase
primary production and consequently induce higher anchovy larval concentration
and higher growth rate. The aforementioned causality is supported by the results of
acoustic stock assessment campaigns that concluded that anchovy biomass increased
from 1716 T to 13,000 T during the period 2000–2001 (García et al. 2003). Agostini
and Bakun (2002) looked in the causes of the significant increase of anchovy fish
stock in period 2000–2001, stressing the existence of an important upwelling
process in the Alboran Sea area during 2001 related to the Atlantic flow through
the Strait of Gibraltar to the Mediterranean Sea as noted before by Cano and Gil
(1984). This upwelling process caused an increase of primary production in Malaga
Bay which resulted in a higher concentration of larvae and individual growth mainly
due to climate and marine environment factors (Macías et al. 2014). It has also been
demonstrated that kinetic energy levels in the NW Alboran region related to wind
regimes favor seasonal upwelling of small pelagic species in the Alboran Sea area
(Ruiz et al. 2013).
Mafalda et al. (2008) compared Spanish Institute of Oceanography stock assessments of 1993 and 1994 analyzing the relationship between Atlantic, Mediterranean,
and mixed water masses and the existence of larvae of different fish species. These
authors showed that the abundance of anchovy larvae was three times higher in 1994
than in 1993. They noted that the increase of fish stocks coincided with SST that was
relatively lower in 1994, namely, between 17
C and 20
C in 1994 and between
22 Fisheries Economics and Management Under the Impact of Human and Varying. . .
769